Tag: macetas de plastico

Over expression of ecdysone during development could explain why BPA causes mouth deformities and increased pupation time in C. riparius 11. In mosquitoes , the vitellogenin gene is a target for ecdysteroid receptor, which can be modulated by the xenoestrogen BPA. This suggests that BPA and other xenoestrogens could have an effect on the production of vitellogenin, the egg yolk protein. This also would lead to altered viability of offspring, which we did not assess. Acetaminophen and the mixture of PPCPs significantly slowed developmental time of C. quinquefasciatus, but antibiotics alone did not. In contrast, Chouaia et al.described delayed larval development of Anopheles stephensi after treatment with the antibiotic rifampicin at 120 µg/ mL. In our study, there was relatively little difference in development of immature mosquitoes between the antibiotic treatments and the controls for the Acetobacteraceae, to which Asaia belongs. It is possible that the antibiotics chosen for this study are not effective in eliminating Asaia. Alternatively, the antibiotics in our study were used at doses much lower than the rifampicin tested by Chouaia et al., and might have achieved similar effects if applied at higher doses. With a combination of antibiotics, hormones and other constituents that occur in PPCP-contaminated reclaimed water, it is difficult to know exactly which chemical is affecting which bacterial family and which bacteria were responsible for the deleterious effects on developmental time. Notably, the antibiotic treatments had approximately 1/3 of the total number of bacteria relative to the control. Therefore even the approximately 8500 counts of Rickettsiaceaein the antibiotic treatments are lower in number than the Enterobacteriaceaefound in control treatments. Surprisingly,macetas de plastico the substantial loss of bacterial counts in the antibiotic only treatments did not slow development.

Although the antibiotics decreased overall bacterial counts in C. quinquefasciatus, W. pipientis appeared to be relatively unaffected. Wolbachia pipientis is susceptible to doxycycline and rifampin. Of the chemicals we tested, oxytetracycline should have had the most impact on Wolbachia. However, because the bacterial counts were relatively similar for W. pipientis in all treatments, we suspect either the oxytetracycline was too dilute to have an effect, it allowed a non-susceptible strain of W. pipientis to dominate, or it is simply ineffective against W. pipientis. However the vast majority of the eight bacterial families were greatly reduced in the antibiotic treatments. Of these families, Enterobacteriaceae and Microbacteriaceae were the most reduced in both the antibiotic and mixture treatments. The family Enterobacteriaceae is highly associated with insect endosymbionts, such as Buchnera in pea aphids. Buchnera bacteria are known to aid the aphid by supplying essential amino acids lacking from a nutritionally deficient diet. Without these endosymbionts the aphids do not develop properly, but the microorganisms apparently have no other direct biological effect on the aphid. The size of the Enterobacteriaceae populations probably had a minimal effect on larval developmental time, as thecounts in the acetaminophen treatment are relatively similar to the hormone-treated group. Additionally, the hormone treated group has a substantially reduced count of Enterobacteriaceae bacteria compared to the control, but showed no significant changes in developmental time. We suspect, therefore, that the acetaminophen is negatively impacting some other biological system in the larvae, but determination will require additional research. The use of reclaimed water for crop irrigation and the release of water from waste treatment plants and farm waste ponds into surface waters is occurring and likely to escalate as demand for fresh water increases. While, the research reported here suggests that PPCPs contaminating reclaimed water will have potentially useful effects for mosquito control, if the data can be extrapolated to other insect species, PPCPs will also have unintended negative effects on other aquatic insects. Very little is known regarding how these contaminants might bio-magnify or change chemically as they move through the food web. The eventual impact on populations is also unknown. Further, combinations of PPCPs may be more important for some insects than individual components.

Additional research is needed not only on aquatic insects living in surface waters, but also on uptake by plants and associated herbivores in terrestrial environments.Endosymbionts, bacterial species known to grow, develop, and vertically transmit in an organisms’ cells, usually for mutualistic symbiosis, are essential to the growth, development, and fecundity of many insect species. Many aphid species, such as Acyrthosiphon pisum, Megoura viciae, and Myzus persicae, rely heavily on endosymbionts to survive on the unbalanced diet of phloem sap. Their bacteriocyte endosymbiont, Buchnera spp, provides essential amino acids. Without Buchnera, aphids demonstrate reduced growth rates and development and produce few or no offspring. However, some endosymbionts in the genus Wolbachia are known to manipulate insects for their own benefit and can also lead to increased vector competency for transmission of human diseases such as West Nile Virus. Wolbachia species are common vertically transmitted endosymbionts in many mosquito species and typically infect reproductive tissue. There are many species of Wolbachia that influence a variety of insect behaviours and life-history traits. Some endosymbionts can also act defensively by killing parasitoid eggs after they are laid in the host . Because endosymbionts play major roles in insect development, they have been proposed for use in insect control . Due to the importance of endosymbionts for development in many insect species, some species vertically transfer endosymbionts . For example, Estes et al. describes the microbiome of dung beetles’ brood balls, which are used to nourish their offspring until they are adults. When the microbiota in the beetle offspring and their female parent were compared in sterilized dung and soil, they had proportionally identical 16S rRNA sequences from their microbiome. Interestingly, over their life stages, the proportions of the families of bacteria in the beetles’ microbiome changed. The predominant family of the first three instars varied by individual. However, from the pupal stage onwards, Enterobacteriaceae was the most common family in the dung beetle. Bees acquire important bacteria through social interaction and also from the environment . Without some of these bacteria, it is thought that honey bees could become more susceptible to outside diseases and increase incidents of colony collapse .

More studies are needed to fully understand the importance of microbiota in mosquitoes as they have been linked to increased transmission of pathogens from mosquitoes to humans. Mosquitoes are common disease vectors, which spend their juvenile stages in aquatic environments . Bacteria from the water, both symbiotic and free-living, have been shown to influence the microbiome of mosquitoes, suggesting that some of their possible endosymbionts are collected from the environment . Consequently, if the environment is altered, and some of these necessary bacteria are reduced/eliminated, there could be detrimental effects on the development of mosquito larvae. Such a removal effect may occur as the result of antibiotic runoff or other pollution,macetas rectangulares and/or environmental changes. For example, Rosi-Marshall et al. showed that common pharmaceuticals in streams will alter the respiration and diversity of biofilms. Pennington et al.reported differences in whole-body micro-biomes and increased developmental times for Culex quinquefasiatustreated with various pharmaceuticals and personal care products .Chemicals intended for human use often occur in aquatic environments and/or enter water supplies through water treatment plant overflow or from use of reclaimed water in water scarce areas. These chemicals can then affect bacterial communities in the water and the associated aquatic insect community. Presence of these contaminants can alter effectiveness of Bacillus thuringiensis subsp. israelensisa pesticide commonly applied for mosquito control . However, little is known about how such contaminants will influence the microbiome of such insects. Similarly, there is a lack of data determining if mosquito bacterial communities vary during the course of larval development; all available studies we are aware of examine only late instar larvae or mixed lower in stars and species, and information regarding mosquitoes’ endosymbionts and their function is very limited or non-existent outside of Wolbachia. Therefore, we describe the differences in the bacterial communities of the mosquito C. quinquefasciatus in multiple distinct larval stages, as well as when these mosquitoes are reared in environments contaminated with ecologically relevant concentrations of PPCPs that commonly occur in combinations in order to provide a baseline for more in-depth studies. In preparation for sequencing, three mosquitoes from each PPCP treatment were collected as second, third and fourth instars, as first instars were too small to collect without damage, and twice washed with 95% ethanol to remove any external microorganisms. Larvae were then transferred to individual sterile 2 mL microcentrifuge tubes with 95% ethanol and stored at -60 ± 3°C in an ultra cold freezer until DNA extraction. DNA was extracted using a Qiagen DNeasy® Blood and Tissue Kit following the manufacturers protocols amended as in Pennington et al.. In addition to mosquitoes, samples of water and water plus diet were also extracted using identical protocols, with the additional step of centrifugation at 2900 rpm in an IEC HN-SII tabletop centrifuge for 1 h to create a pellet. Upon extraction, nucleic acid concentration was quantified using a Nanodrop ND- 2000c Spectrophotometer , to confirm enough genetic material for sequencing. This process revealed no DNA in water or water and diet samples when no mosquitoes werepresent and thus they were not subjected to further analysis because any bacteria would have originated from the mosquitoes, their egg-rafts, or from the air after the water had been altered by the mosquitoes’ various biological processes. Roche 454 bacteria barcoded amplicon pyrosequencing was performed by a commercial sequencing facility .

The procedure used the forward primer 27Fmod and the reverse primer 519Rmodbio in a single-step 30 cycle PCR using HotStarTaq Plus Master Mix . PCR was performed using the following cycle conditions: 94°C for 3 min, followed by 28 cycles of 94°C for 30 s; 53°C for 40 s, 72°C for 1 min; and a final elongation at 72°C for 5 min. After PCR, all amplicons were mixed in equal concentrations and purified using Agencourt Ampure beads . Samples were then sequenced with Roche 454 FLX titanium instruments and reagents following the manufacturer’s guidelines.Operational taxonomic units were chosen by the default 97% identity threshold, which roughly correlates to species , via the UCLUST method as implemented in the pick_otus.py script . Representative OTUs were chosen using the pick_rep_set.py script and default settings. The Greengenes reference database clustered at 97% identity was used to assign taxonomy using the assign_taxonomy.py script. OTUs were counted and summarized using the make_otu_table.py and summarize_taxa.py scripts respectively.There were 658 distinct OTUs at the species level with 58 distinct families; OTUs failed to match any contained within the database and could not be assigned taxonomically. Fifteen families were chosen by their proportionality being greater than or equal to 1% in at least one sample. The cut-off was chosen at 1% as this was assumed to be the minimum to influence larval development. For alpha diversity, multiple rarefactions were performed using the multiple_rarefaction.py script with the lowest rarefaction depth of 2000, the highest rarefaction depth of 21000, a step size of 1000, and a replicate number of ten, which normalizes the data at each depth. Alpha diversity was calculated using the alpha_diversity.py script with the metrics observed species and Shannon Indices. Alpha diversity data was not averaged between replicate mosquitoes as they have been averaged by resampling-replicates and the complications and validity of this is still being considered. Metrics were summarized using the collate_alpha.py script. Statistical analyses were performed using R . Following processing through the QIIME pipeline, “Permutational MANOVA” in the Vegan package was used to compare the OTU data. Independent variables were instar , PPCP treatment and the interaction of the two, with three replicates of each instar in each PPCP treatment and control . PERMANOVA is analogous to MANOVA but is suited to address the non-normality that is commonly associated with count data in ecological community and genetic data . Microbial community data were further examined via principal component analysis performed in the FactoMineR package . PCA and PERMANOVA were conducted on each instar in the individual PPCP and control treatment groups. Following PCA, variables were examined for their contributions and correlation to each of the first two dimensions. Those variables that were ≥ 85% correlated were included in subsequent pairwise comparisons by instar in their respective treatment.

The 2002 Act also created a new Conservation Security Program . This program provides annual payments to farms that use environmentally approved practices in their production operations. Because many farms here in California already apply a number of environmentally approved practices in their operations, this program would provide an additional direct subsidy to farmers on a per acre basis up to relatively small payment limits. But this program has not yet been fully implemented and is very small in total funding.Based on recent data, the Federal Crop Insurance Program provided about $37 billion in protection on about 78 percent of the nation’s insurable acres in 2001 . The crop insurance program has experienced rising participation during the past decade as subsidies have increased and coverage has been extended to more crops. The 2001 level was nearly three times as high as the level in 1990, when crop insurance guarantees amounted to about $13 billion. This protection cost taxpayers about 2.8 billion in 2001. Producers paid about $1.2 billion in premiums and received about $3.1 billion in indemnities. The Agricultural Risk Protection Act of 2000 resulted in increased premium subsidies and adjustments to the formulas used to calculate coverage.For example, the old subsidy level for a coverage level of 50/100 was 55 percent. It now amounts to 67 percent. For a higher coverage level of 75/100, the subsidy level increased from 24percent to 55 percent. This change produced significant cost savings for producers purchasing revenue insurance compared to previous years and also led to a higher number of producers choosing a higher level of coverage. This policy reform has the effect that the crop insurance plays a more important role in the present PSE calculations than it has done under past calculations, because more producers are likely to participate in the program due to the lower cost . On a nationwide basis, the 2000 Act invests an additional $8.2 billion over 5 years to improve federal crop insurance. With regard to California crops, the subsidy resulting from crop insurance in 2001 was substantial for cotton, all grapes, almonds, prunes, apples and wheat. Most other fruits,macetas de plastico vegetables and field crops received only little subsidy as a consequence of participating in the crop insurance program.Irrigation is a key element of the current pattern of agriculture in California.

Water subsidy to California agriculture derives from access to surface irrigation water at prices below cost and below likely market prices for irrigation water if a market were allowed. Much of the reservoir and distribution system that serves agriculture was developed by the federal and state governments. The federal Central Valley Project and the California State Water Project systems of dams and canals are important providers of water storage and delivery to growers. In these projects, water is accumulated and stored in large reservoirs in the northern part of the state and then released into the Sacramento River canals for delivery. Almost half of the water available for use in the San Joaquin Valley comes from CVP and SWP sources. In addition, the All-American Canal diverts water from the Colorado River for use in the Imperial Valley in the far south of California. Imperial Valley dependence on canal water is acute; over 90 percent of valley water comes from federal or state projects. For the PSE calculations we assembled data on irrigation water usage by crop and then developed estimates of the subsidy implicit in the CVP. Based on data from the California Department of Water Resources, we were able to obtain figures on irrigated acreage per crop and irrigation region. This enabled us to calculate the total amount of acre-foot of water applied per crop and region. These calculations are based on average irrigated crop acreage during the 1988-1998 period. For commodities without individual number in DWR data, the share is determined by value of production . The subsidy rates for irrigated water from the Central Valley Project are based on data from the Bureau of Reclamation. We calculated the subsidy rate as the difference of the contract rate that a water district pays per acre-foot and the actual cost per acrefoot. Generally, the contract rate ranges from $10 to $30 per acre-foot for most regions, but it is very low at $2 dollars per acre-foot for most contractors in the Sacramento River region. Subsidy rates varied from $10 to $40 per acre-foot depending on region. The water subsidy for California is estimated to total almost $88 million.Marketing assistance encompasses many programs and departments that provide resident assistance to the agriculture industry. Cooperative Extension and the Agricultural Cooperative Service provide advisory assistance. Inspection services are provided by the Federal Grain Inspection Service, the Food Safety Inspection Service, and the Packers and Stockyards Administration.

The state government also provided approximately $147 million for agricultural plant and animal health, pest prevention and food safety services. Outlays for the Foreign Agriculture Service, Agricultural Marketing Service, and Office of Transportation comprise the federal portion of processing and marketing assistance. For the 1999-2001 period, the average state outlays for California Department of Food and Agriculture marketing, commodities and agricultural services totaled around $60 million. For those commodities with relatively small amounts of total support, marketing assistance provides the bulk of the support. Assessments are subtracted from outlays to determine the contribution to the PSE. Finally, there are state and federal marketing order, board and commissions for many California commodities. These are generally financed by check-off systems that apply a kind of excise tax on the marketed commodity to support promotion or research .Infrastructure support includes federal soil conservation programs, which provide assistance in reducing soil erosion and degradation of resources. While the contribution of these programs to overall support of California agriculture is small, they are included as a separate category for consistency with the PSE calculation. Economy-wide policies include taxes and federal transportation spending. There are various tax benefits for agriculture and foreign sales corporations that indirectly support the agricultural industry. Nelson, Simone and Valdes have compiled the total value of federal tax benefits to agribusiness and have also calculated the value of inland waterway construction and railroad interest rate subsidies. In general, the value of transportation subsidies is relatively small, usually around 2 percent of total support for each commodity. This is likely an over-estimate, however, because the California share in these benefits is likely smaller than the California share of agricultural output . Tax breaks were a larger share of the support, but were not substantial by themselves. We did not include in our PSE calculations the value of state and local real estate tax benefits to agriculture. California, like many other states in the United States, provides for a special taxation rate on agricultural real estate. The state’s Williamson Act, introduced in 1965,macetas rectangulares provides a preferential assessment program for agricultural land. Williamson Act acreage currently represents almost half of California agricultural land. Under the Williamson Act, landowners sign a contract with the appropriate local government agency restricting urban use of that land for ten years.

In return, property under Williamson Act protection is assessed for tax purposes according to its capitalized agricultural income. Capitalized income assessments are usually about half of the market value-based assessments for Williamson Act land; thus landowners receive approximately $120 million in tax benefits. Contracts may be terminated through non-renewal or cancellation. Non-renewal gradually phases in the market value-based assessment over nine years; at the end of the ten-year contract, the land is appraised at full market value. Cancellation of Williamson Act contracts must be approved by the local governing board after conducting public hearings. If the contract cancellation is approved, the landowner pays a penalty of 12.5 percent of the current market value of the land .Dairy policy is discussed in detail above. Here we note only that, in addition to trade protection and internal price policies, the dairy industry receives support from several smaller programs as well. In addition, the dairy industry receives indirect support in the form of subsidies to the grain industry and, especially, the alfalfa hay industry. Hay is important in dairy production, accounting for about 20 percent of total costs. The major subsidy for alfalfa is irrigation water; some have argued that the water subsidy to alfalfa is a major contributor to lower dairy production costs in California. Let’s examine this proposition. Total alfalfa support is about $34 million. Most of this, about $15 million is attributable to the irrigation water subsidy. Some of the alfalfa and other hay grown in the state is consumed by other livestock. Approximately $12 million of the water subsidy to hay is ultimately of benefit to the dairy industry. If the $12 million were added to a subsidy of about one billion dollars, it would raise the overall dairy subsidy from 33.4 percent to 33.6 percent. In other words the effect of irrigation subsidy on dairy is very small, especially compared to the subsidy from other sources.Commodities in this category have little government intervention in their markets. The PSEs range from about 3 to 5 percent of the revenue. There are no significant trade barriers or direct payments for these commodities. The main portion of support comes from input assistance, marketing assistance, broad government infrastructure and economy-wide policies. While these commodities have no explicit export subsidies, they do benefit from foreign market development funding to some degree, especially almonds and strawberries . Crop insurance benefits and disaster payments are also a source of a small amount of support for this group . In the citrus industry, crop insurance and disaster payments comprise almost 30 percent of the support; large payments were made following the 1990 freeze that took a heavy toll on the California citrus industry . Most commodities in this group have some sort of marketing order, either federal, state, or both. The marketing order share of total support ranges from 3 percent to around 25 percent . The share of support from research is relatively high for these commodities, around 25 percent. Nevertheless, since these percentages equal very small PSEs for the horticultural commodities, the overall subsidy is quite small.

One of the major problems in California is that the state’s water is concentrated in the north, but the majority of the state’s urban population and irrigated agriculture is located in the south. California contains 32 million acre-feet of developed water, of which 84 percent is used to irrigate 9.68 million acres of agricultural land. Because such a large proportion of water resources is used for irrigated agriculture, most water management conflicts involve the movement of water to or from irrigated agriculture. While most of the water is used to irrigate field and fodder crops, the high value vegetable and fruit crops generate the majority of agricultural revenues.From the 1950’s to 1970’s different government agencies at the State and Federal level implemented a massive water development program in California. This program was built upon the traditional supply augmentation approach to water development. Unfortunately this approach to water development is flawed. The main weakness of the traditional supply based method is that it assumes that the demand for water is perfectly inelastic and unchanging over time. An inelastic demand assumes that there is little quantitative response to changes in the price of water. Under this planning approach the quantity of water to be delivered by a water project is fixed, and the only question is how to minimize the costs of supplying it. Economic analysis is then performed to see if the total costs of the water project are less than the total benefits. Both the State Water Project and the Federal Central Valley Water Project were developed using the principles of the supply-based approach to water development. The SWP was originally projected to supply an average annual quantity of 4.2 million acre-feet of water in two stages. The first stage of 2.2 million acre-feet was built and put into service in the late 1960’s and early 1970’s. However, subsequent attempts to build the remaining 2 million acre-feet capacity have met with effective opposition from environmental interests, who want to prevent any further water development, and current contractors, who know that the average cost of water delivered by the system will have to increase by up to 300 percent to finance the completion of the planned project.

Data from this trial had a similar trend for the relationship between light interception and yield. In the June Flame cultivar, yield measurements up to 50% light interception had little deviation from the linear model, above this point yield varied significantly. Above 50% light interception, differences in yield are likely caused by other limiting factors such as water or nutrients . This would also explain the poor fit for the model of the C-6 V system. With a canopy that intercepted >50% in all three seasons, yield variation was likely a result of environmental conditions. August Flame systems had more time in the first growing season to fill out their allotted space. This resulted in most systems having >50% light interception in all three seasons. Due to the higher light interception, all models had a poor fit and did not provide confident yield predictions.There were often significantly higher fruit counts and larger fruit compared to the Nema Quad system. In the June Flame 2019 harvest data there was a significant difference detected in slopes comparing fruit size vs fruit per hectare however the difference was related to the C-6 Quad system having the best fit to the model for that season. Overall, this system proved capable of producing yields on par with the current commercial systems. The C-6 V system also proved to be a successful alternative to the current standard systems. Fruit sizes and crop loads matched the Nema Quad system in most seasons. High-density plantings may be more suitable for late-bearing cultivars and growers attempting to reach harvest a season earlier may find it difficult to do so with high-density plantings and an early-bearing cultivar. One drawback is the number of trees that must be managed in this kind of a system. With almost 1800 trees per hectare,macetas de plastico initial costs are higher than a planting with half as many or fewer trees. The C-9 Quad system performed poorly compared to all other systems.

These results would suggest that the system is not capable of matching commercial production. However, systems using the C-9 root stock and higher density plantings have been reported to be more productive than data from this trial suggest. With contrasting results from previous studies, nothing conclusive can be proposed. The Nema Quad system did well as a representation of current commercial standards. The strong benchmark provided by this system highlights the impressive productivity of the C-6 V and C-6 Quad systems. Fossil evidence indicates Olive trees originated 20-40 million years ago in the Oligocene, in what is now the eastern Mediterranean Basin . The olive plant was first cultivated ~ 7000 years ago in the Mediterranean basin . Olives are not native to the Americas. Spanish colonists introduced olive cultivation in present day Peru, Chile, and Argentina in 1500s . The Spanish missionaries brought the olives to California in 1700s . Around 1870, several small orchards with many different European varieties were cultivated for oil along the California coast, from San Diego to Sonoma, and in some foothill areas of the Sierra Nevada Mountains. By 1885, there were 2,000 acres of oil olives planted in California. However, this olive oil industry was not competitive against seed oils or European olive oil imports. The “California Style Black Ripe” olive was developed in the early 1900s, and the California industry focused on table olives, increasing to 35,000 acres by the 1980s . However, in the last four decades, the California table olive industry has declined. Stagnant grower prices, high hand-harvest costs and strong international competition with lower-priced imports have decreased the California table olive industry to 15,500 acres in 2020 . During the same period, the olive oil industry increased to 20,000 acres . This rapid reestablishment of a California olive oil industry was greatly facilitated by cultivars bred to remain small, grow in intensive hedgerow orchards, crop early, and be mechanically pruned and harvested . For the past two decades, olive oil has been promoted as a healthier alternative to other fats and oils.

American olive oil sales have increased 100% from 1991 to 2003 and continue to grow. The US ranks as fourth in world olive oil consumption . This increase in olive oil consumption drove the California olive oil industry to increase domestic production, from 247,500 gallons in 1999-2000 to nearly 400,000 gallons in 2004-2005. Currently, most oil olive orchards are in San Joaquin and Sacramento valleys . Average yields for the past decade have ranged from one to six tons per acre of fresh fruit . However, while consumption is increasing and markets are strong, producers struggle to produce the 5 tons per acre and 190 to 210 gallons of oil per acre needed for economic sustainability. The genus Olea in the family Oleaceae has about 35 species, but Olea Europaea L. is the only one that produces edible fruits. Cultivated olives are medium-size evergreen trees that reach ~ four to eight meters tall. They have dense foliage and bear fruits on the previous year’s apical shoot growth. The simple, lanceolate leaves live for two to three years. The petioles are short, with each node composed of two opposite leaves. The fruit is borne on clusters in the axils of the opposing leaves . Olives grow best in Mediterranean climates with mild winters and warm, dry summers. They are cultivated primarily within the 30° to 45° north and south latitudes. Olives are cold sensitive. When actively growing, temperatures below 0°C damage shoots and kill buds. Temperatures slightly above 0°C decrease bloom. An annual mean absolute minimum temperature below -7°C demarcates the geographical range for olive production . Most cultivars require winter chill of ~ 400 hours below 7°C to break dormancy and bloom. Olives are most sensitive to low and high temperatures during bloom. Flowering can be delayed at low temperatures , and high temperatures can limit pollination and pollen tube growth . The optimal temperature for olive pollen germination and pollen tube growth is 20 to 25°C . Sufficient heat accumulation during the growing season is needed for successful fruit maturation. Full fruit development in olives required 1,225 Celsius degree days . When mature, olives are strongly apically dominant with axillary inflorescences borne on the previous year’s shoot growth. Inflorescences form during the previous season on the growing-shoot leaf axils .

The buds are induced in early summer, initiated in the late fall, and differentiate after dormancy into perfect or imperfect flowers. . Their reproductive or vegetative fate will be determined from mid-June to late October. The process of flower bud formation is called floral induction. The presence of fruit on one-year-old shoots inhabits floral induction on the current year’s shoot growth. Thinning an olive tree within six to seven weeks of flowering increases flowering during the following year . The destruction of seeds of very young fruit without destroying the pericarp flowers can also increase the subsequent year’s flowering . Gibberellins, synthesized in the seeds of a developing fruit, were an important inhibitor of floral induction . Olive inflorescences are 1.5 to 4.0 cm long, with 10 to 35 flowers . The inflorescences have a paniculate structure: flowers grow on the central axis and sometimes sub-branching or secondary bearing-axes can occur . Olive flowers are actinomorphic , and the corollas are composed of four white or yellowish white petals .Olive has an andromonoecious reproductive system,macetas rectangulares producing perfect and male flowers on an individual tree . The imperfect male flower has two stamens, with relatively big, bright yellow anthers and short filaments . In perfect olive flowers, the female reproductive system is a pistil with bi-lobed stigma, a short white style, and a green round ovary . The ovary has two locules or cavities, and within each are two ovules. Fruit development requires fertilization of one of the four ovules . The factors that affect the proportion of perfect flowers include substrate competition, cultivar, and environmental conditions . In a normal year. About 50% of flowers are pistillate .Pollination and fertilization are required for fruit production. During pollination, a pollen grain lands on the stigma and germinates, producing a pollen tube, which grows through the stigmatic surface and down the style to the ovary . Ovules of olives are anatropous and during development, they orient so that the micropyle faces upwards . Like many other angiosperms, after successful pollination, one of the two olive male gametes fuses with the egg cell to become the diploid embryo. The other male gamete unites with two polar nuclei to become the triploid endosperm . Only one of the four ovules isfertilized and develops into a fruit. Vascular bundles separate the future endocarp and mesocarp . Botanically, an olive fruit is a drupe. The mesocarp is the fleshy part of the olive and the endocarp is the stony shell that encloses the fertilized embryo. Some argue olives are allogamous, meaning they require, or produce better, with crosspollination. However, they may self-pollinate but often display self-incompatibility, particularly if temperatures are high during bloom . Olive self-incompatibility is attributed to the slow growth of the pollen tubes of the same cultivar through the stigma, resulting in arrival after the ovule has degenerated . However, no failures in fruit set were detected in cross-pollinated Spanish olive groves, so the delay in self-pollinating cultivars might not be the reason for fruit set failure . Mass abscission of young fruit and unfertilized ovaries are a result of competition for assimilates. In the ‘Gordal Sevillana’, cross pollination reduces the number of shot berries and parthenocarpic fruit with little commercial value.

In the ‘Manzanilla de Sevilla’, cross-pollination increases fruit set. However, in other varieties such as the ‘Arbequina’, there is very little difference in the fruit set in response to cross-pollination . A mature olive tree produces abundant flowers, but only a small portion of them persist as fruits . Anthesis of olives lasted seven weeks, starting at bud break . Most inflorescence axis elongation happens during the third week after BB, massive bract shedding occurs the fourth week after BB, and full bloom occurs seven weeks after BB. Intense abscission of flowers and fruits happens five to seven weeks after FB . During the intense abscission period, imperfect flowers abscise before the perfect flowers and fruits, with overlap . Olive yield depends on the population of viable pistillate flowers, their pollination, fertilization, and persistence as fruits . The number of inflorescences affects final fruit set and the number of fruits within one inflorescence is consistent between years and within cultivars . The final olive fruit set correlates positively with the quantity of pollen during bloom . Ovule longevity is fundamental to flower pollination and fertilization in apples, leading the concept of an Effective Pollination Period . EPP is determined by the longevity of the ovules minus the time required for a pollen tube to grow to the ovule. Longer ovule persistence or viability could increase the EPP and, therefore, potentially fruit set in olives .Olive, like apple, pear, mango, and other fruit trees, are alternate bearing, meaning they produce alternating large and small crops . Alternate bearing does not cause harm to trees , but it destabilizes management, production, and marketing . One hypothesis is that carbohydrate depletion during an “on” year due to fruit growth causes low fruit set in the subsequent “off” year . Olive trees placed in growth chambers under favorable conditions for growth: light, temperature, and high CO2 concentration, had five times more non-structural carbohydrate accumulation than controls . However, the olive trees in the chamber still failed to bloom or set fruit successfully. This observation suggested that the lack of photosynthates was not the primary reason for alternative bearing. The developing fruit is an inhibiting factor for floral induction in olive. Reducing the crop load six to seven weeks after flowering resulted in increased flowering for the following year . Olive fruit seed development is a strong influence on inflorescence development . When olive fruit seeds were killed within six weeks after full bloom, leaving the bearing shoots with seedless fruits, the current year’s shoot growth produced more inflorescences the following year than branches with seeded fruits. Gibberellins, synthesized in seeds of developing fruits, were an important inhibitor of floral induction .